Local Study on Hydrogen and Hydrogen Gas Bubble Formation on a Platinum Electrode

This work investigates the effect of current density on the hydrogen gas bubble formation during electrolysis on a platinum electrode. Local detection of bubble evolution was performed electrochemically by using a hydrogen-collecting microelectrode placed in close proximity of a larger hydrogen-generating platinum electrode. The micro-electrode probe locally measured the concentration of dissolved molecular hydrogen produced during electrolysis. In acidic conditions, it was found that at low electrolysis currents the concentration of dissolved hydrogen could temporarily rise up to 50 times the saturation level, while once a large current was reached, the concentration dropped, increasing the concentration of hydrogen inside gas bubbles, and became independent of the current. Through laser reflectance, the onset of bubble formation was found (similar to-0.7 mA/cm(2)), which was lower than the first bubble observable by naked eye or detected by the microelectrode probe.